1.4-Meter Organic LED TV Sets to Be Unveiled at Consumer Tech Extravaganza

From the editors and reporters of Scientific American , this blog delivers commentary, opinion and analysis on the latest developments in science and technology and their influence on society and policy. From reasoned arguments and cultural critiques to personal and skeptical takes on interesting science news, you'll find a wide range of scientifically relevant insights here. Follow on Twitter @sciam.

Larry Greenemeier is the associate editor of technology for Scientific American, covering a variety of tech-related topics, including biotech, computers, military tech, nanotech and robots. Follow on Twitter @lggreenemeier.

For years manufacturers have tantalized consumers with the promise of organic light-emitting diode (OLED) televisions capable of delivering more brilliant colors (including deeper blacks), and greater levels of contrast and brightness than any other television screen—all with rapid video response rate. OLEDs are already in regular use to provide crystal-clear screens for smart phones, car stereos and digital cameras.

Still, if you went shopping this year for an affordable OLED TV with a display big enough for any room other than a closet, you were sorely disappointed because it doesn’t exist. The situation is likely to change in 2012 when LG and rival Samsung unveil competing 140-centimeter OLED displays—the largest ever made—at next month’s Consumer Electronics Show (CES) in Las Vegas.

What’s the big deal? OLEDs are made by placing thin films of carbon-based materials between two conductors and applying an electrical current to generate a bright light. This makes OLEDs thinner, lighter and more flexible than the crystalline layers in an LED or LCD. Whereas LCDs work by selectively blocking areas of light generated at the back of the display, OLEDs generate light themselves (each pixel is a small light-emitting diode). Because they don’t need to be backlit they consume less power than LCDs.

In terms of pure entertainment value, a 140-centimeter OLED TV is more than three and a half times the size of any other OLED on the market. (LG sells a 38-centimeter display in Europe and its native South Korea for as much as $2,600.) Sony (pdf) and others are developing OLED TVs, but nothing as big as what LG and Samsung are promising. Both models are expected to be available by mid 2012, in time for the Summer Olympics in London.

LG claims that its new OLED TV, which is only five millimeters thick, will have a contrast ratio of more than 100,000:1. The contrast ratio is the proportion of the luminance of a display’s brightest white to that of its darkest black. The higher the ratio the better the viewing experience. To put this in perspective, under optimal (dark) conditions, a movie theater screen achieves a contrast ratio of 500:1. Living rooms are rarely dark enough for a traditional TV to pull off even that level of contrast.

However, complexity and cost of materials have helped keep OLED screen sizes small and prices high. Because an OLED TV has a transistor backplane that controls the brightness of each pixel, millions of these transistors are required to create images on the screen. An OLED is more energy efficient and produces a clearer picture than an LCD screen because it deposits red, green and blue pixels where each of these transistors is positioned. LG claims to have simplified the design of its 140-centimeter display in part by using white OLEDs with color filters. The use of these filters—as well as cheaper, more efficient materials to make the transistors—is helping the company to scale up the size of its OLED displays without a commensurate rise in cost. Neither LG nor Samsung have announced pricing for their new OLED displays.

About the Author: Larry Greenemeier is the associate editor of technology for Scientific American, covering a variety of tech-related topics, including biotech, computers, military tech, nanotech and robots. Follow on Twitter @lggreenemeier.

Wayne, you are correct, in fact, this is a technological compromise that has the OLED purists upset. On paper, OLEDs have the best overall specifications for any direct view display technology ever proposed, however, in execution there are numerous limitations, caveats and deviations from the best: white OLEDs with color filters is one of them. This approach has been developed by Kodak, the originator of small molecule OLEDs. The blue is still lacking in life and efficiency due to its high fermi level electron-hole activation levels. While the white is a broadband emission based on RGB primaries, depositing white gives higher manufacturing yield by simplifying deposition, structure stacking of anode and cathode layers that surround the OLED emissive layer, and the active backplane due to different OLED color voltage thresholds and current drive.
At this stage in OLED’s development (the original Kodak patents have or are expiring soon, including CDT’s, who invented polymer OLEDs – not a commercial contender by any measure). White with color filters is a reasonable compromise for video – low on/off duty cycle and diminished blue contribution to color video.
If you want to be the first and don’t mind paying 3-5x for a display that will not last as long as an LCD/LED display, then go for it. I will not be surprised if they pull back after the produce a few due to yield/performance issues, but the Korean have emerged as the most aggressive display manufacturers. Unfortunately, I have spent over 10 years in the field and know too much about how they work and their present limitations to be persuaded to buy one now. Happy New Year.